Structure and method of forming a laminate structure

ABSTRACT

An elastic laminate structure is provided which is formed from at least one fabric layer and an open cell mesh having first and second strands. The laminate structure is formed such that the first strands are integrally bonded to the first fabric layer. The integrally bonded first strands both penetrate the first fabric layer and bond mechanically and/or chemically to the fibers of the first fabric layer. In addition, the first strands are deformed such that they are substantially flat in shape and substantially coplanar with the fabric layer. The elastic second strands have a substantially elliptical shape. The integral bonding of the first strands and the deformed shape of the first strands and the second strands provides an elastic laminate structure which can be worn about the body without irritation or other discomfort.

This application is a continuation of Ser. No. 08/680,472 filed Jul. 15,1996.

FIELD OF THE INVENTION

This invention relates generally to the field of laminate structuresand, more particularly, to elastic laminate structures formed from apolymeric mesh and at least one fabric layer, wherein improvedelasticity can be provided without sacrificing comfort.

BACKGROUND OF THE INVENTION

Laminate structures have previously been used in a variety of productsincluding elastic absorbent structures such as sweat bands, bandages,diapers, incontinence devices. Several methods for producing theselaminate structures also currently exist. For example, U.S. Pat. No.4,606,694 to Wideman teaches the joining of a gatherable material toeach side of a tensioned elastic web. The gatherable materials arejoined in a pre-tensioned state to the elastic web by self-adheringcompounds, adhesives or thermal bonding. When the tension in the elasticweb is released after joining, the web contracts thereby collecting thegatherable material into folds.

U.S. Pat. No. 4,522,863 to Keck et al. discloses a laminate structurecomprising a mesh having a tissue layer attached to one side and a layerof microfibers attached to the other. The tissue and microfiber layersare attached to the mesh by adhesive, and portions of the layers remainunbonded to the mesh to provide a soft, clothlike feel and appearance.

U.S. Pat. No. 4,977,011 to Smith teaches a laminate structure havingouter layers of low-basis weight breathable material, a central elasticlayer, and an adhesive layer that serves to join all the layerstogether. The elastic layer can be formed from either a single elasticstrand laid between pins to form a multiplicity of nonintersecting linesof elastic, or, alternatively, by a plurality of elastic strandsintersecting at right angles and adhesively joined to the low basisweight breathable material.

Although the above-described laminate structures may be suitable for thepurposes for which they were intended, it is desirable to provide animproved laminate structure having additional benefits and features. Forexample, the previously described structures provide strands whichextend in two distinct directions across the structure (or,alternatively, teach a complex method for aligning a single strand in asingle direction between pins). When resulting laminate structures suchas these are cut, however, the cut edges of the strands can protrude oncut sides of the structure such that they can be a source of irritationif the structure is worn next to the body, as is the case with bandages,body wraps, diapers, incontinence devices and the like. Further, if anelastic laminate structure having a large modulus value (i.e., the ratioof stress to strain) is desired, elastic strands having a largecross-sectional area are generally required. However, large strands ofthis type can produce a rough or "nubby" feeling when placed in contactwith the body. Consequently, it would be desirable to further provide anelastic laminate structure which can provide elastic strands havinglarge cross-sectional areas and yet which is still comfortable to beworn about the body. The present invention provides an improved laminatestructure and method for forming such structure which can accommodatedesigns having the above-described structural features and benefits.

SUMMARY OF THE INVENTION

A laminate structure is provided comprising first fabric layer and amesh having a plurality of first strands which intersect a plurality ofsecond strands. The first and second strands intersect at apredetermined and substantially uniform angle which preferably is about90 degrees. Although the first and second strands can be elastic,inelastic, or a combination thereof it is preferred that the firststrands are inelastic while the second strands are elastic. Such aconfiguration provides a laminate structure which is inelastic along thedirection of the first strands and elastic along the direction of thesecond strands.

The first and second strands have a softening temperature at a bondingpressure such that application of the bonding pressure at the softeningtemperature of the first strands integrally bonds at least one of thefirst stands to the first fabric layer. Further, it is desirable thatapplication of the bonding pressure deforms at least one of the firststrands into a substantially flat shape which is also coplanar with theinner surface of the first fabric layer. For ease of manufacture andprocessing, the softening temperatures of the first and second strandsare preferably distinct at the bonding pressure, the softeningtemperature of the first strands being lower than the softeningtemperature of the second strands. So as to avoid overlap or joining ofadjacent first strands when the first strands are deformed byapplication of the bonding pressure, the first strands preferably have astrand density of between about 2 and about 10 first strands percentimeter and a cross-sectional area of between about 0.0005 cm² andabout 0.03 cm².

The laminate structure of the present invention can be formed by eithera static plate process or a roller nip process. In the static plateprocess, a first surface is provided in the form of a substantiallyresilient plate while a second surface is provided in the form of asubstantially non-resilient plate. The mesh and fabric are juxtaposedand the bonding pressure is applied to the first strands of the mesh byappropriately moving the first surface toward the second surface.Because the first surface is heated to a temperature such that the firststrands are at their softening temperature for the applied bondingpressure, the first strands integrally bond to the first fabric layer.Preferably, the application of the bonding pressure also deforms thefirst strands into a substantially flat shape which is also coplanarwith the first fabric layer and deforms the second strands into asubstantially elliptical shape.

In the nip process, three surfaces in the form of rollers are providedwherein a substantially resilient first surface is in surface contactwith a substantially non-resilient second surface (i.e., forming aninterference nip) and the second surface is adjacent a substantiallynon-resilient third surface such that a gap is formed therebetween(i.e., forming a gapped nip). The first fabric layer and mesh arejuxtaposed and fed over the third surface which is heated to atemperature such that the second strands reach their softeningtemperature for the deformation pressure which is applied at the gap.Application of the deformation pressure to the second strands at the gappreferably deforms the second strands into a substantially ellipticalshape. The juxtaposed fabric and mesh are then fed over the secondsurface which is heated to a temperature such that the first strandsreach their softening temperature with respect to the bonding pressurewhich is applied at the interference nip between the first and secondsurfaces. Application of the bonding pressure to the first strands attheir softening temperature integrally bonds the first strands to thefirst fabric layer. Preferably, application of the bonding pressure alsodeforms the first strands into a substantially flat shape which is alsocoplanar with the inner surface of the first fabric layer. Thesubstantially flat shape, integral bonding of the first strands to thefirst fabric layer, and the substantially elliptical shape of the secondstrands advantageously provides a laminate structure which can be wornabout the body (e.g., in bandages, body wraps and the like) withoutirritation or other discomfort.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming the invention, it is believed the same will bebetter understood from the following description taken in conjunctionwith the accompanying drawings in which:

FIG. 1 is an exploded view of a mesh and first fabric layer prior tobeing formed into a laminate structure made in accordance with thepresent invention;

FIG. 2 is a partial perspective view of a laminate structure made inaccordance with the present invention, wherein a portion of the fabriclayer has been removed to show the integrally bonded first strands;

FIG. 2a is an enlarged partial perspective view of an integrally bondedfirst strand of the laminate structure of FIG. 2;

FIG. 3 is a schematic representation of a gapped nip process accordingto the present invention for forming the laminate structure of FIG. 2;and

FIG. 4 is a schematic representation of a plate process according to thepresent invention for forming the laminate structure of FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the present preferredembodiments of the invention, examples of which are illustrated in theaccompanying drawings wherein like numerals indicate the same elementsthroughout the views. FIG. 1 is an exploded view of the components oflaminate structure 20 prior to its formation (laminate structure 20 isshown in FIG. 2). As illustrated, laminate structure 20 is formed from afirst fabric layer 22 and an open cell mesh 24 having a plurality offirst strands 26 and a plurality of second strands 28. As shown in FIG.2, laminate structure 20 preferably has at least one structuraldirection D, wherein at least a portion of structural direction D iselastic. More preferably, laminate structure 20 provides a structuraldirection D which is elastic along the direction and entire length ofsecond strands 28. As used herein, the phrase "structural direction"(e.g., D) is intended to mean a direction which extends substantiallyalong and parallel to the plane of outer fabric surface 31 of firstfabric layer 22. Laminate structure 20 can be incorporated into avariety of products (not illustrated) wherein it is desired to provideat least one structural direction which is partially or entirely elasticalong its length. Examples of such products include elastic diapers,incontinence products, bandages, body wraps and the like.

Although it is preferred that laminate structure 20 provide at least onestructural direction D which is elastic, it is further contemplated thatlaminate structure 20 can be inelastic such that no elastic structuraldirections are provided. Alternatively, laminate structure 20 can alsobe provided with a structural direction over which a portion of thelength thereof is elastic and a portion of the length thereof isinelastic. As used herein, the term "elastic" is intended to mean adirectional property wherein an element or structure has a recovery towithin about 10 percent of its original length L_(o) in the subjectdirection after being subjected to a percentage strain ω_(%) of greaterthan 50 percent. As used herein, percentage strain ω_(%) is defined as:

    ω.sub.% =[(L.sub.f -L.sub.o)/L.sub.o ]*100

Where

L_(f) =Elongated length

L_(o) =Original length

For consistency and comparison, the recovery of an element or structureis preferably measured 30 seconds after release from its elongatedlength L_(f). All other elements or structures will be consideredinelastic if the element or structure does not recover to within about10 percent of its original length L_(o) within 30 seconds after beingreleased from a percentage strain ω_(%) of 50%. Inelastic elements orstructures would also include elements or structures which partially orwholly separate, fracture and/or permanently/plastically deform whensubjected to a percentage strain of ω_(%) 50%.

Referring now to FIG. 2, mesh 24 comprises a plurality of first stands26 which intersect or cross (with or without bonding to) a plurality ofsecond strands 28 at nodes 30 at a predetermined angle α, therebyforming a net-like open structure having a plurality of apertures 32.Each aperture 32 is defined by at least two adjacent first strands(e.g., 34 and 36) and at least two adjacent second strands (e.g., 38 and40) such that apertures 32 are substantially rectangular (preferablysquare) in shape. Other aperture configurations, such as parallelogramsor circular arc segments, can also be provided. Such configurationscould be usefull for providing non-linear elastic structural directions.It is preferred that first strands 26 are substantially straight andsubstantially parallel to one another, and, more preferably, that secondstrands 28 are also substantially straight and substantially parallel toone another. Most preferably, first strands 26 intersect second strands28 at nodes 30 at a predetermined angle α of about 90 degrees. Each node30 is an overlaid node, wherein first strands 26 and second strands 28are preferably joined or bonded (although it is contemplated thatjoining or bonding may not be required) at the point of intersectionwith the strands still individually distinguishable at the node however.However, it is believed that other node configurations such as merged ora combination of merged and overlaid would be equally suitable.

Although it is preferred that first and second strands be substantiallystraight, parallel, and intersect at an angle α of about 90 degrees, itis noted that first and second strands can intersect at other angles α,and that first strands 26 and/or second strands 28 can be aligned incircular, elliptical or otherwise nonlinear patterns relative to oneanother. Although for ease of manufacture it is contemplated that firststrands 26 and second strands 28 have a substantially circularcross-sectional shape prior to incorporation into laminate structure 20(as shown in FIG. 1), first and second strands can also have othercross-sectional shapes such as elliptical, square, triangular orcombinations thereof.

The process of manufacturing mesh 24 for incorporation into the presentinvention involves the selection of an appropriate material for thefirst and second strands. Preferably, the material of first strands 26is chosen so that first strands 26 can maintain second strands 28 inrelative alignment prior to forming laminate structure 20. It is alsodesirable that the materials of first and second strands be capable ofbeing deformed (or initially formed) into predetermined shapes uponapplication of a predetermined pressure or a pressure in combinationwith a heat flux, as described in more detail hereafter. These deformedshapes (e.g., elliptical second stands, substantially flat first strandsand the like) provide a laminate structure 20 which can be comfortablyworn about the body without irritation or other discomfort. It isfurther desirable that the material chosen for first strands 26 providean adhesive-like property for joining a portion of second stand outersurface 44 of deformed second strands 29 to a portion of first fabriclayer inner surface 46.

The material of first strands 26 should also be capable of integrallybonding with first fabric layer 22 as part of forming laminate structure20. As described in more detail hereafter, first strands 26 can beintegrally bonded to first fabric layer 22 by application of a pressureor a pressure in combination with a heat flux. As used herein, thephrase "integrally bonded" and its derivatives is intended to mean thata portion of a strand outer surface (e.g., first strand outer surface42) of an integrally bonded strand (e.g., integrally bonded firststrands 27) has penetrated into and bonded with first fabric layer 22.The portion of the strand outer surface of an integrally bonded strandwhich penetrates first fabric layer 22 can bond mechanically (e.g., asby encapsulating, encircling or otherwise engulfing) and/or chemically(e.g., polymerizing, fusing or otherwise chemically reacting) withfibers 43 of first fabric layer 22, as shown in FIG. 2a. With regard topenetration, integrally bonded preferably means that a portion of thestrand outer surface has penetrated at least about 10% of fabricstructural thickness T of first fabric layer 22 in laminate structure20, and, more preferably, a portion of the strand outer surface haspenetrated at least about 25 percent of fabric structural thickness T(various amounts of penetration are generally shown in FIG. 2). Mostpreferably, a portion of the strand outer surface has penetrated about100% of fabric structural thickness T. Further, because integrallybonded strands enhance the comfort of laminate structure 20 when wornabout the body, it is preferred that between about 10 percent and about50 percent of first strands 26 are integrally bonded to first fabriclayer 22 of laminate structure 20. More preferably, between about 50percent and about 90 percent of first strands 26 are integrally bondedto first fabric layer 22. Most preferably, about 100 percent of firststrands 26 are integrally bonded.

The above-described benefits can be achieved by selecting a first strandmaterial having a softening temperature which is lower than thesoftening temperature of second strands 28 relative to the processingpressures used to form laminate structure 20. As used herein, the phrase"softening temperature" is intended to mean the temperature at which amaterial flows or deforms under an applied pressure. Typically, heat isapplied to a material to achieve a softening temperature. This generallyresults in a decrease in the viscosity of the material which may or maynot involve a "melting" of the material the melting being associatedwith a latent heat of fusion. Thermoplastic materials tend to exhibit alowering in viscosity as a result of an increase in temperature allowingthem to flow when subjected to an applied pressure. It will beunderstood that as the applied pressure increases, the softeningtemperature of a material decreases and therefore a given material canhave a plurality of softening temperatures because the temperature willvary with the applied pressure. For ease of manufacturing andprocessing, and when utilizing generally polymeric materials for strands26 and 28, it is desirable that the difference in softening temperaturesbetween the material of first strands 26 and the material of secondstrands 28 is at least about 10 degrees centigrade, when both materialsare subjected to the same applied pressure (e.g., the processingpressure). More preferably, the difference in softening temperaturesbetween the first and second strands is at least about 20 degreescentigrade. As will be understood, the difference in softeningtemperatures between the materials of first strands 26 and secondstrands 28 facilitates the integral bonding of first strands 26 to firstfabric layer 22 without integrally bonding second strands 28 to thefirst fabric layer when both strands are subjected to a predeterminedpressure or predetermined pressure and heat flux. In addition to theselection of first and second strand materials for softening point,second strands 28 are preferably formed from a material which renderssecond strands 28 appropriately elastic such that laminate structure 20provides a structural direction along the direction of second strands 28which is also appropriately elastic as desired.

Polymers such as polyolefins, polyamides, polyesters, and rubbers (e.g.,styrene butadiene rubber, polybutadiene rubber, polychloroprene rubber,nitrile rubber and the like) have been found to be suitable materialsfor forming the first and second strands of mesh 22. Other materials orcompounds (e.g., adhesive first strands) having different relativesoftening temperatures or elasticities can be substituted so long as thematerial provides the previously described benefits. Additionally,adjunct materials can be added to the base materials comprising firstand second strands (e.g., mixtures of pigments, dyes, brighteners, heavywaxes and the like) to provide other desirable visual, structural orfunctional characteristics. Mesh 22 may be formed from one of a varietyof processes known in the art.

So that mesh 22 can be integrally bonded to first fabric layer 22, it isdesirable that first fabric layer 22 have a basis weight of less thanabout 100 gm/m², a caliper of less than about 0.1 cm, and comprisefibers having a fiber size of less than about 20 denier per filament.More preferably, for products such as body wraps, bandages and the like,first fabric layer will have a basis weight of less than about 50 gm/m²,a fiber size of less than about 5 denier per filament and a caliper ofless than about 0.02 cm. For ease of manufacture and cost efficiency,first fabric layer 22 is preferably formed from a nonwoven fabric havingfibers formed, for example, from polyethylene, polypropylene,polyethylene terepthalate, nylon, rayon, cotton or wool. These fiberscan be joined together by adhesives, thermal bonding, needling/felting,or other methods known in the art to form first fabric layer 22.Although it is preferable that first fabric layer 22 is formed from anon-woven fabric, other fabrics such as woven, three dimensional formedfilms, and two dimensional apertured flat films would be equallysuitable.

The softening temperature of first fabric layer 22 (at the subjectprocessing pressures) should be greater than any of the processingtemperatures applied to mesh 22 in forming laminate structure 20. Inaddition, first fabric layer 22 of the present invention preferably hasa modulus of less than about 100 gm force per cm at a unit strain ω_(u)of at least about 1 (i.e., L_(f) =2×L_(o)) in a direction along secondstrands 28 when it is formed into laminate structure 20. As used herein,the term "modulus" is intended to mean the ratio of an applied stress σto the resulting unit strain ω_(u), wherein stress σ and unit strainω_(u) are:

    σ=F/W

    ω.sub.u =(L.sub.f -L.sub.o)L.sub.o

Where

F=Applied force

W=Orthogonal dimension of the element or structure subjected to theapplied force F (typically the structure width)

L_(f) =Elongated length

L_(o) =Original length

For example, a 20 gram force applied orthogonally across a 5 cm widefabric would have a stress σ of 4 grams force per cm. Further, if theoriginal length L_(o) in the same direction as the applied force F were4 cm and the resulting elongated length L_(f) were 12 cm, the resultingunit strain ω_(u) would be 2 and the modulus would be 2 grams force percm.

It is believed that a first fabric layer having a modulus of less thanabout 100 grams force per cm in a subject fabric direction will, whenthe subject fabric direction is juxtaposed co-directional with elasticsecond strands 28 in laminate structure 20, provide a laminate structure20 with a modulus along the direction of second strands 28 that islargely a function of the material properties, size and arrangement ofsecond stands 28. In other words, the modulus of first fabric layer 22will be low enough that the modulus of the second strands will largelydetermine the modulus of laminate structure 20 in the subject direction.This configuration is especially useful if it is desired that laminatestructure 20 provide an elastic structural direction along the directionof laminate second strands 29.

If first fabric layer 22 does not inherently provide the desiredmodulus, first fabric layer can be subjected to an activation processbefore or after forming laminate structure 20. As taught for instance inU.S. Pat. No. 4,834,741 issued to Sabee on May 30, 1989, the substanceof which is hereby incorporated by reference, subjecting first fabriclayer 22 to an activation process (either separately or as part oflaminate structure 20) will plastically deform first fabric layer 22such that it will provide the desired modulus. In an activation process,such as that taught by Sabee, a first fabric layer 22 (or laminatestructure incorporating same) is passed between corrugated rolls toimpart extensibility thereto by laterally stretching first fabric layer22 in the cross-machine direction. First fabric layer 22 isincrementally stretched and drawn to impart a permanent elongation andfabric fiber orientation in the cross-machine direction. This processcan be used to stretch first fabric layer 22 (or multiple fabric layers)before or after joinder to the laminate structure 20. This preferablyprovides a laminate structure 20 which can be extended in an elasticstructural direction with minimal force as fabric layer 22 (and anyadditional fabric layers) have initially been "activated" or separatedin this direction, thereby providing a low modulus in the subjectdirection such that the laminate structure modulus is primarily afunction of laminate second strands 29.

Laminate structure 20 is preferably formed by juxtaposing first fabriclayer 22 and mesh 24 and applying a predetermined pressure or apredetermined pressure and heat flux, depending upon the selected meshand fabric materials, so that first strands 26 are integrally bonded tofirst fabric layer 22. In addition to integrally bonding first strands26 to first fabric layer 22, it is desirable that the above-describedprocess deform first strands 26 so that the shape of integrally bondedfirst strand outer surface 42 is substantially flat. The phrase"substantially flat" and its derivatives, as used herein, means thatintegrally bonded first strands 27 have a major dimension M (i.e., thelargest dimension parallel to the major axis of the strand cross sectionas shown in FIG. 2) at least about 2 times the length of a minordimension N (i.e., the smallest dimension parallel to the minor axis ofthe strand cross section as shown in FIG. 2). Thus, it should be clearthat an integrally bonded first strand 27 can have irregularities inouter surface 42 (i.e, peaks and valleys and the like, as shown in FIG.2a) and still be within the intended meaning of substantially flat. Morepreferably, it is desirable that a portion of outer surface 42 ofintegrally bonded first strands 27 is also substantially coplanar withfirst fabric layer inner surface 46 such that minor dimension N is aboutequal to or less than structural thickness T of first fabric layer 22and substantially all of minor dimension N is located within structuralthickness T, as generally shown in FIG. 2. It is further contemplatedthat variations in the substantially flat and coplanar shapes ofintegrally bonded first strands 27 can occur along the length of firststrands 27 without deviating from scope of these definitions. In otherwords, due to processing variations, it is noted that portions ofintegrally bonded first strands 27 can be substantially flat and/orcoplanar while other portions along the same strand may not. Theseconfigurations are still considered to be within the definitions ofsubstantially flat and coplanar as set forth above.

The above-described shapes of integrally bonded first strands 27advantageously provide a laminate structure 20 wherein strands 27 do notprotrude in a manner which would cause irritation or other discomfortwhen laminate structure 20 is cut (thereby exposing the ends ofintegrally bonded first strands 27) and worn about the body. As such, itis preferred that at least about 50 percent of integrally bonded firststrands 27 are substantially flat and coplanar, and, more preferably, atleast about 75 percent of integrally bonded first strands 27 aresubstantially flat and coplanar. Most preferably, about 100% ofintegrally bonded first strands 27 are substantially flat and coplanar.

In contrast to the substantially flat and coplanar shape of integrallybonded first strands 27 of laminate structure 20, laminate secondstrands 29 are preferably only joined (as opposed to integrally bonded)to first fabric inner surface 46, as shown in FIG. 2, by application ofthe above-described pressure and heat flux. It is contemplated, however,that second strands 28 can also be integrally bonded to first fabriclayer 22 if so desired. The integral bonding of first strands 26 tofirst fabric layer 22 can also be performed such that first strands 26act as an adhesive to intermittently join second strands 28 to firstfabric inner surface 46 at nodes 30. Alternatively, second stands 28 cancomprise a self-adhering material which aids in joining a portion ofsecond strand outer surfaces 44 to first fabric layer inner surface 46.

As seen in FIG. 3, laminate structure 20 is preferably manufactured by agapped nip process comprising a substantially resilient first surface 48(e.g., formed from a silicone or other deformable rubber), asubstantially non-resilient second surface 50 (e.g., formed from steelor the like), and a substantially non-resilient third surface 52,wherein these surfaces are provided in the form of rollers. First andsecond surfaces are positioned in surface contact to one another therebyforming an interference nip 54 while second surface 50 is spacedadjacent to third surface 52 such that a nip 56 having a gap is formedtherebetween. The gap is preferably sized such that the smaller diameterfirst strands 26 pass easily therethrough while larger diameter secondstrands 28 are contacted by second surface 50 and third surface 52.Preferably, the rollers comprising first, second, and third surfaces arein relative vertical alignment, as illustrated generally in FIG. 3.

First fabric layer 22 is juxtaposed adjacent to mesh 24 such that whenfed around third surface 52, as seen in FIG. 3, mesh 24 is preferablyadjacent to third surface 52 and disposed between the third surface andfirst fabric layer. Third surface 52 is heated to a temperature T3which, in combination with the feed rate of juxtaposed first fabriclayer 22 and mesh 24 over third surface 52, raises the temperature ofsecond strands 28 to their softening temperature relative to thedeformation pressure P_(d) exerted at gapped nip 56 upon second strands28. Because first strands 26 are preferably exposed to pressure muchless than deformation pressure P_(d) because of their small diameter,first strands 26 preferably have not reached their softening temperaturebecause of this low applied pressure at this nip and therefore undergolittle if any deformation thereat. In contrast, second strands 28 aredeformed into a substantially elliptical shape at gapped nip 56 becausedeformation pressure P_(d) is fully applied such that second strands 28have reached their softening temperature at this applied pressure. Itshould be readily apparent that even though the first and second strandsmay be at about the same physical temperature at gapped nip 56, secondstrands 28 are at their softening temperature while first strands 26 arenot because each are exposed to a different applied pressure. Theelliptical cross-sectional shape of second strands 28 is desirable ifthe undeformed cross section of the second strands would otherwiseproduce a "nubby" or rough feel when laminate structure 20 is worn aboutthe body. Preferably, the post-nip structural thickness I of juxtaposedfirst fabric layer 22 and mesh 24 is about 50% of the pre-nip structuralthickness S.

As juxtaposed first fabric layer 22 and mesh 24 pass through gapped nip56, first fabric layer 22 is preferably oriented adjacent second surface50 and disposed between second surface 50 and mesh 24. Second surface 50is preferably heated to a temperature T2 which, in combination with thefeed rate of juxtaposed first fabric layer 22 and mesh 24 over secondsurface 50, raises the temperature of first strands 26 to theirsoftening temperature relative to the bonding pressure P_(b) exerted atinterference nip 54. The bonding pressure P_(b) is preferably low enoughthat second strands 28 preferably have not reached their softeningtemperature at interference nip 54 and therefore undergo littleadditional deformation thereat. In contrast, as juxtaposed first fabriclayer 22 and mesh 24 pass through interference nip 54, first strands 26are integrally bonded to first fabric layer 22 by the application ofbonding pressure P_(b) from the first and second surfaces at the nipbecause first strands 26 have reached their softening temperature,relative to applied bonding pressure P_(b), from the heat flux providedby temperature T2. Resilient first surface 48 provides a bondingpressure P_(b) that is uniformly applied to first strands 26 betweensecond strands 28 due to the conforming nature of resilient firstsurface 48. More preferably, the application of pressure P_(b) and heatflux from second surface 50 at temperature T2 is sufficient to alsodeform first strands 26 into substantially flat shaped and integrallybonded first strands 27. Most preferably, the application of pressureand heat flux is sufficient to also deform first strands 26 intointegrally bonded first strands 27 which are substantially coplanar withfirst fabric inner surface 46.

The feed rate of juxtaposed first fabric layer 22 and mesh 24 throughfirst, second and third surfaces can be adjusted so that first andsecond strands have a sufficient residence time adjacent heated secondand third surfaces so that these strands can be softened and deformed asdescribed herein. It has been found, however, that a smaller gapped nip56 is required as this feed rate is increased to maintain the samerelative pressure and hence deformation of second strands 28.

Based upon the foregoing described nip process, it has been found thatthe following will form a satisfactory laminate structure 20 having anelastic structural direction along the direction of laminate secondstrands 29: a carded non-woven first fabric layer 22 formed fromthermally bonded polypropylene and having a 32 gram per m² basis weight,a fiber size of about 2.2 denier per filament, a caliper of betweenabout 0.01 cm to about 0.03 cm, a modulus of about 100 grams force percm at a unit strain ω_(u) of 1 (such a fabric being marketed byFibertech, of Landisville , N.J., under the name of Phobic Q-1); and amesh 24 comprising first strands 26 formed from polyethelylene andsecond strands 28 formed from a styrene or butadiene block copolymer(such a mesh being manufactured by Conwed of Minneapolis, Minn. andmarketed under the name T50018). Specifically, the juxtaposed Phobic Q-1fabric and T50018 mesh having a preformed structural thickness S ofabout 0.12 cm are fed at a rate of between about 5 and about 15 metersper minute over third surface 52 which is heated to a temperature T3 ofabout 90 degrees centigrade. In a preferred arrangement, the juxtaposedfabric and mesh pass through nip 56 having a gap of between about 0.01and about 0.02 cm such that they emerge from the nip having anintermediate structural thickness I of about 0.056 cm. Preferably,second surface 50 is heated to a temperature T2 of about 135 degreescentigrade as the juxtaposed fabric and mesh pass over second surface 50and through inference gap 54.

In addition to forming a laminate structure of the present invention viathe above-described dual nip process, such laminate structure can alsobe formed by a process providing a first surface (e.g., 48) and a secondsurface (e.g., 50) in the form of corresponding plates, such as shown inFIG. 4. As discussed previously, first surface 48 preferably issubstantially resilient, while second surface 50 is substantiallynon-resilient. First fabric layer 22 is juxtaposed with mesh 24 suchthat first fabric layer 22 is immediately adjacent second surface 50.First surface 48 is preferably heated to a temperature T1 and a bondingpressure P_(b) is applied to the juxtaposed fabric and mesh by movingfirst surface 48 toward second plate surface 50 appropriately. Becausetemperature T1 heats first strands 26 to their softening temperature forthe applied bonding pressure P_(b), application of the bonding pressureP_(b) integrally bonds first strands 26 to the first fabric layer 22.More preferably, application of the bonding pressure P_(b) also deformsfirst strands 26 into a substantially flat shape which is also coplanarwith inner surface 46 of the first fabric layer. Most preferably,application of bonding pressure P_(b) also deforms the second strandsinto a substantially elliptical shape.

Using the Phobic Q-1 fabric and T50018 mesh combination described above,a satisfactory laminate structure 20 having first strands 26 integrallybonded to first fabric layer 22 can be provided if first surface 48 isheated to a temperature T1 of about 120 degrees centigrade, and abonding pressure P_(b) of between 350 to 700 grams force per cm² isapplied for between about 10 and about 20 seconds.

It is believed that properly selecting the strand density, standcross-sectional area, and/or the melt index of first strands 26 (iffirst strands 26 are formed of a polymer) is necessary in order toprovide a laminate structure 20 having an elastic structural directionalong the direction of the second stands 28. Improper selection ofstrand density, strand cross-sectional area, and/or melt index of firststrands 26 can result in a laminate structure wherein portions ofintegrally bonded first strands 27 can overlap or merge together inlaminate structure 20. Such merging or overlap of integrally bondedfirst strands 27 can result in only small portions of laminate secondstrands 29 being able to extend or elongate when subjected to a tensileforce, as opposed to the elongation being distributed alongsubstantially the entire length of substantially all of laminate secondstrands 29 absent this overlap. To minimize this condition, the stranddensity, strand cross-sectional area, and/or melt index of first strands26 should be selected such that integrally bonded first strands 27 havea strand coverage S of less than about 50%. As used herein, the phrase"strand coverage" is intended to be a measure of the amount of surfacearea of first fabric layer inner surface 46 which is in contact withintegrally bonded first strands 27 of the present invention. Strandcoverage S_(c) is defined as:

    S.sub.c =(E/F)* 100

Where

E=strand centerline distance between any adjacent integrally bondedfirst strands 27, as shown in FIG. 2

F=strand edge distance F between any adjacent integrally bonded firststrands 27, as shown in FIG. 2

The measurements of E and F can be taken at any cross section throughlaminate structure 20 of the present invention between any adjacentintegrally bonded first strands 27.

The phrase "strand density", as used herein, is intended to mean thenumber of subject strands per centimeter along a strand transverse tothe subject strands. For example, first strands 26 have a strand densitywhich can be measured over a predetermined length A of a second strand28, as shown in FIG. 2. Likewise, second strands 28 have a stranddensity which can be measured over a predetermined length B of a firststrand 26. The phrase "strand cross-sectional area", as used herein, isintended to mean the cross-sectional area of any first strand 26 of mesh24 when measured according techniques known in the art. For example, theselected strand can be encapsulated in a resin, sliced, and thecross-sectional area measured by means of an magnifying instrument, suchas a light microscope or scanning electron microscope.

The melt index of a polymer measures the ability of the polymer to flowwhen subjected to a given temperature and pressure. A polymer having alow melt index will be more viscous (and therefore not flow as readily)at a given temperature than a polymer having a higher melt index. Thus,it is believed that first strands 26 comprising a polymer having a highmelt index will have a greater tendency to merge or overlap duringapplication of a given pressure and heat flux than first strands 26comprising a polymer having a lower melt index and subjected to the samepressure and heat flux. Because of this variability, the polymer formingfirst strands 26 can be selectively chosen, in conjunction with thestrand density and strand cross-sectional area, to provide apredetermined melt index such that first strands 26 are integrallybonded to first fabric layer 22 with a strand coverage S_(c) of about 50percent. In addition, varying the polymer melt index can also beespecially useful where it is desired to increase the density of thefirst fabric layer 22 while maintaining the same processing conditions.In this situation, the polymer of first strands 26 can be changed toprovide a higher melt index such that first strands 26 can more easilypenetrate and bond with fabric layer 22 when subjected to thepredetermined pressure and heat flux. Consequently, the same level ofintegral bonding can be achieved without changing the processingconditions despite the increased density of first fabric layer 22.

Based upon the foregoing, it is believed that first strands 26 shouldpreferably be aligned so as to provide a strand density of between about2 and about 10 strands per centimeter in conjunction with a strandcross-sectional area of between about 0.0005 and about 0.03 cm² so thatmerger or overlap of integrally bonded first strands 27 in laminatestructure 20 can be avoided. More preferably, first stands 26 have astrand density of between about 3 and about 6 in conjunction with astrand cross-sectional area of between about 0.001 and about 0.005 cm².A melt index of between about 2 and about 15 (as measured per ASTMD1238) in conjunction with the above-described stand density and strandcross-sectional area values has been found to be satisfactory.

With regard to second strands 28, it is believed that the stranddensity, strand cross-sectional area, and the modulus of second strands28 can also can affect the elastic properties of laminate structure 20(e.g., the modulus of structure 20) in the direction along the secondstrands (i.e., along direction D of FIG. 2). For example, as the stranddensity and/or the strand cross-sectional area of second strands 28increases, the modulus of laminate structure 20 will decrease. For alaminate structure of the present invention to be incorporated into aproduct to be worn about the body, it is desirable that a modulus ofbetween about 100 grams force per cm and about 250 grams force per cm ata unit strain ω_(u) of about 1 be provided. It is believed thatproviding second strands 28 having a strand density of between about 2and about 5, a cross-sectional area of between about 0.003 cm² and about0.02 cm², and comprising a styrene butadiene block copolymer willprovide a laminate structure having the preferred modulus in a directionalong second strands 28. The modulus of laminate structure 20 can bemeasured by techniques known in the art. For example, the modulus oflaminate structure 20 can be measured using a universal constant rate ofelongation tensile tester, such as Instron Model #1122 (whichmanufactured by Instron Engineering Corporation of Canton, Mass.).

Laminate structure 20 can also be subjected to various additionalpost-formation processes known in the art. For example, a laminatestructure made in accordance herewith can comprise additional fabriclayers which are joined to the laminate structure so as to furtherimprove the wearability and comfort of the structure. The additionalfabric layers can be secured to the laminate structure by a uniformcontinuous layer of adhesive, a patterned layer of adhesive, or an arrayof separate lines, spirals, or spots of adhesive. An adhesive found tobe satisfactory is manufactured by Findlay Adhesives of Wauwatosa, Wis.and marketed under the name H2031. Alternatively, the additional fabriclayers can be attached by heat bonds, pressure bonds, ultrasonic bonds,dynamic mechanical bonds or any other suitable method as are known inthe art.

Having shown and described the preferred embodiments of the presentinvention, further adaptation of the improved laminate structure can beaccomplished by appropriate modifications by one of ordinary skill inthe art without departing from the scope of the present invention. Anumber of alternatives and modifications have been described herein andothers will be apparent to those skilled in the art. For example, broadranges for the physically measurable parameters have been disclosed forthe inventive laminate structure as preferred embodiments of the presentinvention, yet it is contemplated that the physical parameters of thelaminate structure can be varied to produce other preferred embodimentsof improved laminate structure of the present invention as desired. Inaddition, it should be readily apparent that the alignment, properties,and composition of first strands 26 can be interchanged with those ofsecond strands 28, or additional strands can be provided (e.g., aplurality of third strands etc.) to alter or enhance the properties of alaminate structure made in accordance with this invention. Accordingly,the scope of the present invention should be considered in terms of thefollowing claims and is understood not to be limited to the details ofthe structures and methods shown and described in the specification anddrawings.

What is claimed is:
 1. A mesh comprising a plurality of first strandswhich intersect or cross a plurality of second strands at an angle α,thereby forming a net-like open structure having a plurality ofapertures, wherein said first and second strands have a softeningtemperature at a bonding pressure such that said softening temperatureof said first strands is less than said softening temperature of saidsecond strands.
 2. A mesh according to claim 1 wherein said angle α is90°.
 3. A mesh according to claim 2 wherein said second strands areelastic along the partial or entire longitudinal direction of saidsecond strands.
 4. A mesh according to claim 3 wherein said firststrands are inelastic.
 5. A mesh according to claim 4 wherein said meshhas a first strand density of said first strands, measured transverse tothe longitudinal direction of said plurality of first strands, of fromabout 2 strands/cm to about 10 strands/cm.
 6. A mesh according to claim5 wherein said first strand density is from about 3 strands/cm to about6 strands/cm.
 7. A mesh according to claim 5 wherein said first strandshave a cross-sectional area of from about 0.0005 cm² to about 0.03 cm².8. A mesh according to claim 7 wherein said first strands have across-sectional area of from about 0.001 cm² to about 0.005 cm².
 9. Amesh according to claim 7 wherein said mesh has a second strand densityof said second strands, measured transverse to the longitudinaldirection of said plurality of said second strands, of from about 2strands/cm to about 5 strands/cm.
 10. A mesh according to claim 9wherein said second strands have a cross-sectional area of from about0.003 cm² to about 0.02 cm².
 11. A mesh according to claim 10 whereinsaid first strands are deformed into a substantially flat shape uponapplication of said bonding pressure or said pressure in combinationwith a heat flux to said first strands.
 12. A mesh according to claim 11wherein said second strands are deformed into a substantially ellipticalshape upon application of said bonding pressure or said pressure incombination with a heat flux to said second strands.
 13. A meshaccording to claim 12 wherein said first strands have a melt index offrom about 2 to about
 15. 14. A mesh according to claim 13 wherein saidsoftening temperature of said first strands is at least about 10° C.less than said softening temperature of said second strands when bothsaid first and second strands are subjected to the same said bondingpressure.
 15. A mesh according to claim 14 wherein said softeningtemperature of said first strands is at least about 20° C. less thansaid softening temperature of said second strands when both said firstand second strands are subjected to the same said bonding pressure. 16.A mesh according to claim 14 wherein said first strands are adhesive forjoining a portion of said deformed second strands to a portion of one ormore fabric layers.
 17. A mesh according to claim 16 wherein said firststrands are integrally bonded with said one or more fabric layers.
 18. Amesh according to claim 17 wherein said first strands have said firststrand density and said cross-sectional area, such that said firststrands are selectively chosen to provide said melt index such that saidfirst strands integrally bond to said one or more fabric layers with astrand coverage of said one or more fabric layers of less than or about50%.
 19. A mesh according to claim 18 wherein said first and secondstrands are selected from the group of materials consisting ofpolyolefins, polyamides, polyesters, block copolymers, rubbers, andmixtures thereof.
 20. A mesh according to claim 19 wherein said secondstrands comprise a styrene butadiene block copolymer.
 21. A meshaccording to claim 18 wherein from about 10% to about 50% of saidplurality of first strands are integrally bonded with said one or morefabric layers.
 22. A mesh according to claim 21 wherein from about 50%to about 90% of said plurality of first strands are integrally bondedwith said one or more fabric layers.
 23. A mesh according to claim 22wherein about 100% of said plurality of first strands are integrallybonded with said one or more fabric layers.
 24. A mesh according toclaim 18 wherein said first strands are integrally bonded with said oneor more fabric layers such that a portion of said first strandspenetrates at least about 10% of the structural thickness of said one ormore fabric layers.
 25. A mesh according to claim 24 wherein said firststrands are integrally bonded with said one or more fabric layers suchthat a portion of said first strands penetrates at least about 25% ofthe structural thickness of said one or more fabric layers.
 26. A meshaccording to claim 25 wherein said first strands are integrally bondedwith said one or more fabric layers such that a portion of said firststrands penetrates about 100% of the structural thickness of said one ormore fabric layers.